Modeling of Critical Areas for DRP Runoff and Targeting Strategies
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Transcript of Modeling of Critical Areas for DRP Runoff and Targeting Strategies
Modeling of Critical Areas for DRP Runoff and Targeting Strategies
Rem Confesor Jr.Research Scientist
NCWQR, Heidelberg University
Team Meeting #5 Great Lakes Protection Fund Grant
A Phosphorus Soil Test MetricTo Reduce Dissolved Phosphorus Loading to Lake Erie
July 24, 2013
Watershed Modeling
CONSTRAINTS:
SPACE & TIMEresolution
Precipitation
Infiltration Runoff flow
Yearly Runoff flow = (x)Precipitation + y(Infiltration) + Constant
Spatially lumped across the whole watershed, Yearly time step
Issues:
a. One precipitation value for the whole watershed.
b. Model is not a good representation of reality.
c. Coefficients are unknown: need for calibration.
A very simple conceptual model…
Precipitation (P)
Infiltration (I)Runoff
Flow (R)
Evapo-transpiration (ET)
Groundwaterrecharge (G)
Lateral subsurface
Flow (L)
Evaporation (E)
Soilstorage
(S)
S = P - ET - E - I - R; I = G + L;Discharge (Q) = (a)R + (b)L + c
Basic spatial unit
A little bit of improvement…
Digital elevation model(slope/terrain)
Land use/ crop cover
Soil typeHydrologic Response Units (HRUs)
+
+
The hydrologic response unit (HRU)- basic spatial unit:unique combination of slope, landuse, & soil.
Terrain
Weather
Soil
Land use/crop cover
Agricultural practices & mgt.: tillage, fertilizer, etc.
Flow, sediment,
nutrients (N & P), etc.
The SWAT Model:
Physically-based.
Daily time step.
Long-term simulation of effects of changes in ag. management.
“RELATIVE” output changes due to these management changes.
SWAT SETUP: CROP ROTATION
2006, Corn
2007, Soybean
2008, Corn
2009, Soybean
Baseline to NoTill + IncBaseline to NoTill
Change in DRP, lb/acre P2O5
Change in DRP, lb/acre P2O5
NoTill + In TO Disc Plowed + InNoTill + Bcast TO NoTill + In
Change in Particulate P, lb/acre P2O5
Baseline to NoTill + InBaseline to NoTill
NoTill + In TO Disc Plowed + InNoTill + Bcast TO NoTill + In
Change in Particulate P, lb/acre P2O5
419-448-2204
http://www.heidelberg.edu/academiclife/distinctive/ncwqr
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